From affce8159cda2ed571305077fd06e5e81f917308 Mon Sep 17 00:00:00 2001
From: ayn2op <ayn2op@gmail.com>
Date: Sat, 17 Aug 2024 18:27:59 +0530
Subject: [PATCH] refactor: use go 1.23 iterators

---
 cmd/guilds_tree.go      | 21 ++++++++++++---------
 cmd/messages_text.go    | 10 +++++-----
 pkg/itertools/filter.go | 15 +++++++++++++++
 pkg/itertools/map.go    | 13 +++++++++++++
 4 files changed, 45 insertions(+), 14 deletions(-)
 create mode 100644 pkg/itertools/filter.go
 create mode 100644 pkg/itertools/map.go

diff --git a/cmd/guilds_tree.go b/cmd/guilds_tree.go
index da14aa3..871dfc2 100644
--- a/cmd/guilds_tree.go
+++ b/cmd/guilds_tree.go
@@ -3,9 +3,11 @@ package cmd
 import (
 	"fmt"
 	"log"
+	"slices"
 	"sort"
 	"strings"
 
+	"github.com/ayn2op/discordo/pkg/itertools"
 	"github.com/diamondburned/arikawa/v3/discord"
 	"github.com/diamondburned/arikawa/v3/gateway"
 	"github.com/gdamore/tcell/v2"
@@ -88,12 +90,11 @@ func (gt *GuildsTree) channelToString(c discord.Channel) string {
 		s = c.Name
 		// If the name of the channel is empty, use the recipients' tags
 		if s == "" {
-			rs := make([]string, len(c.DMRecipients))
-			for _, r := range c.DMRecipients {
-				rs = append(rs, r.Tag())
-			}
+			recipients := itertools.Map(slices.Values(c.DMRecipients), func(r discord.User) string {
+				return r.Tag()
+			})
 
-			s = strings.Join(rs, ", ")
+			s = strings.Join(slices.Collect(recipients), ", ")
 		}
 	case discord.GuildAnnouncement:
 		s = "a-" + c.Name
@@ -128,10 +129,12 @@ func (gt *GuildsTree) createChannelNode(n *tview.TreeNode, c discord.Channel) *t
 }
 
 func (gt *GuildsTree) createChannelNodes(n *tview.TreeNode, cs []discord.Channel) {
-	for _, c := range cs {
-		if c.Type != discord.GuildCategory && !c.ParentID.IsValid() {
-			gt.createChannelNode(n, c)
-		}
+	orphanChannels := itertools.Filter(slices.Values(cs), func(c discord.Channel) bool {
+		return c.Type != discord.GuildCategory && !c.ParentID.IsValid()
+	})
+
+	for _, c := range slices.Collect(orphanChannels) {
+		gt.createChannelNode(n, c)
 	}
 
 PARENT_CHANNELS:
diff --git a/cmd/messages_text.go b/cmd/messages_text.go
index 83310db..2666516 100644
--- a/cmd/messages_text.go
+++ b/cmd/messages_text.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"slices"
 	"strings"
 	"time"
 
@@ -59,8 +60,8 @@ func (mt *MessagesText) drawMsgs(cID discord.ChannelID) {
 		return
 	}
 
-	for i := len(ms) - 1; i >= 0; i-- {
-		mainFlex.messagesText.createMessage(ms[i])
+	for _, m := range slices.Backward(ms) {
+		mainFlex.messagesText.createMessage(m)
 	}
 }
 
@@ -337,8 +338,7 @@ func (mt *MessagesText) delete() {
 
 	mt.Clear()
 
-	for i := len(ms) - 1; i >= 0; i-- {
-		mainFlex.messagesText.createMessage(ms[i])
+	for _, m := range slices.Backward(ms) {
+		mainFlex.messagesText.createMessage(m)
 	}
-
 }
diff --git a/pkg/itertools/filter.go b/pkg/itertools/filter.go
new file mode 100644
index 0000000..fa04471
--- /dev/null
+++ b/pkg/itertools/filter.go
@@ -0,0 +1,15 @@
+package itertools
+
+import "iter"
+
+func Filter[I any](in iter.Seq[I], predicate func(I) bool) iter.Seq[I] {
+	return func(yield func(I) bool) {
+		for i := range in {
+			if predicate(i) {
+				if !yield(i) {
+					return
+				}
+			}
+		}
+	}
+}
diff --git a/pkg/itertools/map.go b/pkg/itertools/map.go
new file mode 100644
index 0000000..8a03c2b
--- /dev/null
+++ b/pkg/itertools/map.go
@@ -0,0 +1,13 @@
+package itertools
+
+import "iter"
+
+func Map[I, O any](in iter.Seq[I], f func(I) O) iter.Seq[O] {
+	return func(yield func(O) bool) {
+		for i := range in {
+			if !yield(f(i)) {
+				return
+			}
+		}
+	}
+}